1 /* MN10300 Atomic counter operations
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
19 * Atomic operations that C can't guarantee us. Useful for
20 * resource counting etc..
24 * Make sure gcc doesn't try to be clever and move things around
25 * on us. We need to use _exactly_ the address the user gave us,
26 * not some alias that contains the same information.
32 #define ATOMIC_INIT(i) { (i) }
37 * atomic_read - read atomic variable
38 * @v: pointer of type atomic_t
40 * Atomically reads the value of @v. Note that the guaranteed
41 * useful range of an atomic_t is only 24 bits.
43 #define atomic_read(v) ((v)->counter)
46 * atomic_set - set atomic variable
47 * @v: pointer of type atomic_t
50 * Atomically sets the value of @v to @i. Note that the guaranteed
51 * useful range of an atomic_t is only 24 bits.
53 #define atomic_set(v, i) (((v)->counter) = (i))
55 #include <asm/system.h>
58 * atomic_add_return - add integer to atomic variable
59 * @i: integer value to add
60 * @v: pointer of type atomic_t
62 * Atomically adds @i to @v and returns the result
63 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
65 static inline int atomic_add_return(int i, atomic_t *v)
70 local_irq_save(flags);
74 local_irq_restore(flags);
80 * atomic_sub_return - subtract integer from atomic variable
81 * @i: integer value to subtract
82 * @v: pointer of type atomic_t
84 * Atomically subtracts @i from @v and returns the result
85 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
87 static inline int atomic_sub_return(int i, atomic_t *v)
92 local_irq_save(flags);
96 local_irq_restore(flags);
101 static inline int atomic_add_negative(int i, atomic_t *v)
103 return atomic_add_return(i, v) < 0;
106 static inline void atomic_add(int i, atomic_t *v)
108 atomic_add_return(i, v);
111 static inline void atomic_sub(int i, atomic_t *v)
113 atomic_sub_return(i, v);
116 static inline void atomic_inc(atomic_t *v)
118 atomic_add_return(1, v);
121 static inline void atomic_dec(atomic_t *v)
123 atomic_sub_return(1, v);
126 #define atomic_dec_return(v) atomic_sub_return(1, (v))
127 #define atomic_inc_return(v) atomic_add_return(1, (v))
129 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
130 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
131 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
133 #define atomic_add_unless(v, a, u) \
136 c = atomic_read(v); \
137 while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
142 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
144 static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
149 local_irq_save(flags);
151 local_irq_restore(flags);
154 #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
155 #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
157 /* Atomic operations are already serializing on MN10300??? */
158 #define smp_mb__before_atomic_dec() barrier()
159 #define smp_mb__after_atomic_dec() barrier()
160 #define smp_mb__before_atomic_inc() barrier()
161 #define smp_mb__after_atomic_inc() barrier()
163 #include <asm-generic/atomic.h>
165 #endif /* __KERNEL__ */
166 #endif /* _ASM_ATOMIC_H */